• Journal of KIISE:Software and Applications
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• v.29 no.3
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• pp.167-179
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• 2002

In this paper, we propose a new acoustic model for characterizing segmental features and an algorithm based upon a general framework of hidden Markov models (HMMs) in order to compensate the weakness of HMM assumptions. The segmental features are represented as a trajectory of observed vector sequences by a polynomial regression function because the single frame feature cannot represent the temporal dynamics of speech signals effectively. To apply the segmental features to pattern classification, we adopted segmental HMM(SHMM) which is known as the effective method to represent the trend of speech signals. SHMM separates observation probability of the given state into extra- and intra-segmental variations that show the long-term and short-term variabilities, respectively. To consider the segmental characteristics in acoustic model, we present segmental-feature HMM(SFHMM) by modifying the SHMM. The SFHMM therefore represents the external- and internal-variation as the observation probability of the trajectory in a given state and trajectory estimation error for the given segment, respectively. We conducted several experiments on the TIMIT database to establish the effectiveness of the proposed method and the characteristics of the segmental features. From the experimental results, we conclude that the proposed method is valuable, if its number of parameters is greater than that of conventional HMM, in the flexible and informative feature representation and the performance improvement.

• Journal of Radiation Protection and Research
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• v.44 no.4
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• pp.128-148
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• 2019

Massive environmental monitoring has been conducted continuously since the Fukushima Daiichi Nuclear Power accident in March of 2011 by different monitoring methods that have different features together with migration studies of radiocesium in diverse environments. These results have clarified the characteristics of radiological environments and their temporal change around the Fukushima site. At three months after the accident, multiple radionuclides including radiostrontium and plutonium were detected in many locations; and it was confirmed that radiocesium was most important from the viewpoint of long-term exposure. Radiation levels around the Fukushima site have decreased greatly over time. The decreasing trend was found to change variously according to local conditions. The air dose rates in environments related to human living have decreased faster than expected from radioactive decay by a factor of 2-3 on average; those in pure forest have decreased more closely to physical decay. The main causes of air dose rate reduction were judged to be radioactive decay, movement of radiocesium in vertical and horizontal directions, and decontamination. Land-use categories and human activities have significantly affected the reduction tendency. Difference in the air dose rate reduction trends can be explained qualitatively according to the knowledge obtained in radiocesium migration studies; whereas, the quantitative explanation for individual sites is an important future challenge. The ecological half-lives of air dose rates have been evaluated by several researchers, and a short-term half-life within 1 year was commonly observed in the studies. An empirical model for predicting air dose rate distribution was developed based on statistical analysis of an extensive car-borne survey dataset, which enabled the prediction with confidence intervals. Different types of contamination maps were integrated to better quantify the spatial data. The obtained data were used for extended studies such as for identifying the main reactor that caused the contamination of arbitrary regions and developing standard procedures for environmental measurement and sampling. Annual external exposure doses for residents who intended to return to their homes were estimated as within a few millisieverts. Different forms of environmental data and knowledge have been provided for wide spectrum of people. Diverse aspects of lessons learned from the Fukushima accident, including practical ones, must be passed on to future generations.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.585-597
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• 2008

The aim of this study was to find an analytic solution to the problem of determining the optimal capacity (lot-size) of a batch-storage network to meet demand for a finished product in a system undergoing random failures of operating time and/or batch material. The superstructure of the plant considered here consists of a network of serially and/or parallel interlinked batch processes and storage units. The production processes transform a set of feedstock materials into another set of products with constant conversion factors. The final product demand flow is susceptible to short-term random variations in the cycle time and batch size as well as long-term variations in the average trend. Some of the production processes have random variations in product quantity. The spoiled materials are treated through regeneration or waste disposal processes. All other processes have random variations only in the cycle time. The objective function of the optimization is minimizing the total cost, which is composed of setup and inventory holding costs as well as the capital costs of constructing processes and storage units. A novel production and inventory analysis, the PSW (Periodic Square Wave) model, provides a judicious graphical method to find the upper and lower bounds of random flows. The advantage of this model is that it provides a set of simple analytic solutions while also maintaining a realistic description of the random material flows between processes and storage units; as a consequence of these analytic solutions, the computation burden is significantly reduced.

• The Journal of Sustainable Design and Educational Environment Research
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• v.18 no.1
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• pp.27-37
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• 2019

This study investigated and analyzed the rise and fall trend of enrolled students during the recent 30 years with the subject of 607 elementary schools in 11 Education Support Centers (25 Gu-districts) in Seoul to provide the basic data related to establishing the school accommodation plan of the Seoul Education Office. In particular, the study focuses on the 53 small schools in Seoul and examines whether a correlation exists between the 8 factors of the school accommodation plan and the increasing and decreasing of enrolled student numbers. First, 'school establishment policy' should not be a short-term therapy but a long-term and predictable sustainable policy. Second, among the eight factors, there seems to be a very high correlation between the 'aged low-rise house districts' and 'spatially isolated areas'. Third, 'close-packed apartment complexes' and 'rental apartment complexes' are also highly correlated. Fourth, the planning factors such as 'joint school districts, the reconstruction of apartment complexes and the connection to commercial districts' seem to be correlated to some degree. Therefore, further studies are needed to overcome these problems.

• Korea Trade Review
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• v.41 no.3
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• pp.1-25
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• 2016

This study reviews international discussions about the trade-labor linkage and examines the labor chapters of FTAs enforced by the US and the EU from a comparative perspective. Since early 1990s, starting from the NAFTA, the US has included forceable labor provisions in its FTAs and this trend continues to the TPP which was concluded in October 2015. On the other hand, the EU's labor provisions in its FTAs have been composed of promotional elements on labor rights based on cooperations and dialogues. These different features of labor provisions in the US and European FTAs are mainly due to the motives of the FTAs of the US and the EU respectively as well as their domestic situations with regards to domestic law and institutional set-ups. The coordination of labor provisions involves a long-term institutional as well as regulatory convergence which triggers not only economic but also social changes, compared to a relatively short-term effect of tariff elimination. For Korea which has been a FTA partner country both with the US and the EU, it is significant to keep the different characteristics in the labor provisions in mind, particularly in the process of its implementation. Concerning the implementation of Korea-US FTA, it might be problematic if Korean law and its regulatory practice on labor-management relations do not comply with that of the US. The Korea-EU FTA case can also have an indirect impact on Korea's labor laws since it stipulates in its provisions that both parties should have discussions not only within each government but also with the civil communities including NGOs. Thus, Korea should pay more attention to the true meaning in labor provisions of both FTAs in order to promote its firms to be equipped with the right labor-management system in their operations abroad.

• Journal of Korean Academy of Nursing
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• v.4 no.3
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• pp.63-79
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• 1974

1. The purpose of this study. The purpose of this study is to plan and investigate short-term nursing education of two-years associate degree program to produce middle-level professional nurses which are needed by-society and nation. Current nursing education in Korea is divided into four years degree program, three years diploma program Even (though) there are differences in the aims of their education, the curriculums are not much different between the education for producing leaders which is its basic purpose and training middle-level professional nurses. Therefore the purpose of associate degree program lies in minimizing the waste of time and finance which are invested for long-term education for middle-level professional nurses. And also this coincide with the policy of national technical training and definite supply of nurse manpower according to health policy for effective role and ability of nurse. 2. The method of study. This is based on the study of literature, research on the actual condition and investigation of opinion- through questionnaire. L) The study of literature: Domestic and foreign literatures for two years associate degree program were studied and investigated. 2) Research on the actual condition : Current three years nursing education program was collected and analysed. 3) Investigation of opinion. The problem of curried nursing education system and the possibility of two years associate degree program were investigated through questionnaire. 3. The result of the study. 1) The trend of recent nursing education. a. The aims of nursing in past chiefly taking care of physical disease of patient has recently changed to nursing of character including physical, mental, socio-economic, educational and psychological condition. b. For the performing systematic and effective nurse's duty according to her role, the-change of educational system which is classified as a range of education the period of education and certificate after graduation has been enforced or fulfilled. c. Nursing education also has a trend to become a collage or two years associate degree program which can get same legal protection as other educational institutions whose basic purpose is education. Attached nursing school to hospital is getting disappeared because of disadvantage of educational system. 2) Problems. Depending upon research on actual condition of current 3 years nursing education program. a. There are too many subjects. b. Contents of education could be doubled because major subjects are subdivided in detail. c. The credits for graduation are too heavy comparing to the period of study or the ability of students. (The necessary credits are 150.8 for three years according to actual investigation 4. There is no certain standard in organizing curriculum therefore there are too much differences between schools. 4. Basic Plan. The plan for two years associate degree program in nursing education depending on demand of professional nursing field of society is based on following items. 1) Training middle-level professional nurse lay emphasis on liberal arts and basic major field. 2) Liberal arts are divided into required and optional subjects and students could take courses by choice. 3) Major subjects are compound together by fields and they become the sciences of nursing Ⅰ,Ⅱ,Ⅲ,Ⅳ and every items has its educational purposes and contents major study includes laboratory practice and clinical experience. 4) The required credits for graduation are to which means 17-18 credits a semester. The above has been planned to solve the problems of current three years nursing education program. In conclusion for the achievement of this system, following items are needed. 1) It is necessary to change educational administration and system such as amendment of educational law or order of educational application of law. 2) Qualified professors should be available to understand and develope the idea or purpose of this educational system. 3) Local medical institutions should be opened widely and educational for clinical training. 4) The job after graduation should he secured positively.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.563-576
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• 2023

In this study nitrogen dioxide (NO₂), formaldehyde (HCHO) from the Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI), OMI/ Microwave Limb Sounder (MLS) tropospheric column ozone (TCO), and Airkorea ground-based O₃ data were analyzed to examine the photochemical reaction relationship between tropospheric ozone and its precursors nitrogen oxides (NOx) and volatile organic compounds (VOCs). As a result of analyzing the trend of long-term changes from 2006 to 2020 using OMI satellite data, TCO showed an increasing trend, NO₂ steadily decreased, and HCHO continued to increase in Northeast Asia. In addition, formaldehyde nitrogen dioxide ratio (FNR; HCHO/NO₂ ratio), an indicator of ozone sensitivity, is gradually increasing, which means that the VOC-limited regime is decreasing. This study conducted a sensitivity analysis of ozone generation using TROPOMI FNR and ground-based ozone (O₃) over the recent years (2019~2022) to identify the possible cause for the continuous increase of ozone in Korea. Similar to the previous studies, VOC-limited and transitional regimes appeared in megacities, and VOC-limited regimes also appeared in areas where major power plants were located. In VOC-limited regimes, in other words, areas where NOx is excessively saturated, the reduction in NOx emissions may have weakened the ozone titration and thus led to the increase of ozone. Therefore, VOC emissions should be reduced in the short term rather than NOx emissions to reduce ozone concentrations under the VOC-limited regime.

• Journal of Intelligence and Information Systems
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• v.28 no.4
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• pp.157-177
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• 2022

Investors are trading stocks by keeping a close watch on the order information submitted by domestic and foreign investors in real time through Limit Order Book information, so-called price current provided by securities firms. Will order information released in the Limit Order Book be useful in stock price prediction? This study analyzes whether it is significant as a predictor of future stock price up or down when order imbalances appear as investors' buying and selling orders are concentrated to one side during intra-day trading time. Using classification algorithms, this study improved the prediction accuracy of the order imbalance information on the short-term price up and down trend, that is the closing price up and down of the day. Day trading strategies are proposed using the predicted price trends of the classification algorithms and the trading performances are analyzed through empirical analysis. The 5-minute KOSPI200 Index Futures data were analyzed for 4,564 days from January 19, 2004 to June 30, 2022. The results of the empirical analysis are as follows. First, order imbalance information has a significant impact on the current stock prices. Second, the order imbalance information observed in the early morning has a significant forecasting power on the price trends from the early morning to the market closing time. Third, the Support Vector Machines algorithm showed the highest prediction accuracy on the day's closing price trends using the order imbalance information at 54.1%. Fourth, the order imbalance information measured at an early time of day had higher prediction accuracy than the order imbalance information measured at a later time of day. Fifth, the trading performances of the day trading strategies using the prediction results of the classification algorithms on the price up and down trends were higher than that of the benchmark trading strategy. Sixth, except for the K-Nearest Neighbor algorithm, all investment performances using the classification algorithms showed average higher total profits than that of the benchmark strategy. Seventh, the trading performances using the predictive results of the Logical Regression, Random Forest, Support Vector Machines, and XGBoost algorithms showed higher results than the benchmark strategy in the Sharpe Ratio, which evaluates both profitability and risk. This study has an academic difference from existing studies in that it documented the economic value of the total buy & sell order volume information among the Limit Order Book information. The empirical results of this study are also valuable to the market participants from a trading perspective. In future studies, it is necessary to improve the performance of the trading strategy using more accurate price prediction results by expanding to deep learning models which are actively being studied for predicting stock prices recently.

• Journal of Soil and Groundwater Environment
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• v.11 no.2
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• pp.56-67
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• 2006

Trends of variation in groundwater levels, electrical conductivities and water temperatures obtained from the national groundwater monitoring stations (95 shallow and 169 deep wells) of Korea were evaluated. For the analysis, both parametric (linear regression) and non-parametric (Mann-Kendall test, Sen's test) methods were adopted. Results of linear regression analysis indicated that about 50% of the monitoring wells showed increasing trends of groundwater levels, electrical conductivities, and water temperatures and the others showed decreasing trends. However, the non-parametric analyses with monthly median values revealed that $14.8{\sim}20.0%$ of water levels were decreased, $24.2{\sim}36.9%$ of electrical conductivities were increased, and $27.4{\sim}32.5%$ of water temperatures were increased at a confidence level of 99%. Highly proportions of increasing or decreasing trends were unexpected and they resulted from the relatively short term of data collection (maximum 6 years). Meanwhile, the investigation of groundwater around the national groundwater monitoring stations showed that the decreasing or increasing trends of water levels, electrical conductivities, themselves, didn't indicate directly groundwater hazards such as groundwater depletion or groundwater contamination. Both the values and variation rates (slopes) of water level, electrical conductivity and temperature in the longer period are considered simultaneously. This study is the first comprehensive work in analyzing trends of groundwater data obtained from the national groundwater monitoring stations. Based on this study, the periodical and regular analysis of groundwater data is essentially required to grasp the overall variational trend of groundwater resources in the country.

• Journal of Ginseng Research
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• v.33 no.2
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• pp.115-126
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• 2009

To evaluate the efficacy and safety of red ginseng on women's health-related quality of life (QOL) and sexual function. A randomized, double-blind, placebo-controlled, crossover clinical study was performed. The main efficacy was measured using the Female Sexual Function Index (FSFl) and the 36-Item Short-Form Health Survey (SF-36). Twenty-four healthy, married women aged 30-45 years with FSFl scores below 25 were randomly divided into two groups: the red-ginseng group (N=12) and the placebo group (N=12). During the first six-week period (Study 1), each group was given red ginseng or placebo twice a day. Before the start of the second six-week period (Study 2), a crossover design was chosen with a two-week break (washout period). Interchanging the two groups after the washout period, red ginseng and placebo were given to each group. The outcomes were measured before and after each six-week period. Overall, 23 participants completed the study. In Study 1, the changes relative to the baseline in the FSFl total score were 22.50% and 22.99% for red ginseng and placebo, respectively. In Study 2, the relative changes were 8.14% for red ginseng and 6.29% for placebo. The results showed a greater improving trend in Study 1 with respect to all of the participants' sexual functions, but no significant difference was found between the groups (P=0.9567). After taking red ginseng, all the participants exhibited an improving trend in the desire domain of FSFl, but no significant difference was shown. In the measurement of SF-36, no significant difference was likewise shown. After taking red ginseng, though, all the participants exhibited an improving trend in the physical functioning (PF) domain of SF-36, with no significant difference. Moreover, there was no significant adverse event related to red ginseng. The QOL and sexual function of the study participants in the red-ginseng group were mostly improved, but no statistically significant effect of red ginseng was shown. It is supposed that this result was partly due to the affirmative impression of red ginseng in Korea. Thus, it is anticipated that a long-term clinical trial will show a significant effect of red ginseng on the QOL and sexual function.